System of electrical distribution.



J. L. WOODBRIDGE.

SYSTEM OF ELECTRICAL DISTRIBUTION.

APPLICATION FILED MAR. 23. 1911.

1,096,879. Patented Iday'19, 1914.

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JOSEPH LESTER WQODBRIDGE, 0F vIHILALDELPHIA, PENNSYLVANIA.

SYSTEM OF ELECTRICAL DISTRIBUTION.

To all whom it may concern:

Be it known that I, JOSEPH LESTER WOODBRIDGE, a citizen of the United States, and resident of Philadelphia, in the county of Philadelphia, State I of Pennsylvania, haveinvented certain new and useful Improvements in Systems of Electrical Distribution, of which the following is a specification.

My invention relates to systems in which a dynamo electric machine is driven by a gasolene engine or similar source of power,

and is employed in conjunction with a storage battery for supplying current to electric lights or other translating devices, and the object of the invention-is to provide means whereby the dynamo may be utilized as a motor for starting the engine, receiving current from the battery for this purpose, and after the engine is started may be utilized as a generator for supplying current to the lamps and battery. In order to develop the necessary torque for starting the engine with thesmallest capacity of apparatus, and at the same time avoid exeesslve armature speed when the engine is driving the dynamo as a generator, I provide two different sets of gear wheels between -the engine and dynamo shafts which are selective in their operation, one set controlling the speed ratio between the shafts when the engine is driving the dynamo, and the other set controlling this ratio when the dynamo is operating as a motor driving the engine- These results are accomplished by special clutch devices, which ob- .viate the necessity of shifting the gears. I

also provide means forchanging the armature and field connections, and at the same time changing the connections of the battery cells from series to parallel. p

M invention will be more clearly understoo by reference to the following description in connection with the accompanying drawings, in which' Figure 1 is a diagrammatic view of a system embodying features of the invention; Figs. 2 and 3 are end views of the two pinions drawn to an enlarged scale showing the clutch devices, and Fig. 4 illustrates a different type of clutch. I

Referring to Fig. 1, F and F are the field windings, and A and A? are the corresponding armatures of two dynamo electric machines mounted on a common shaft, on which are mounted the pinions. P and P, which mesh with the gears G and G Specification of Letters Patent. Application filed March 23, 1911.

B and B of which B Patented May 19, 1914. Serial No. 816,424.

a gasolene or other explosive engine whose cylinders are shown at C and C". A circuit 12 is shown supplying the lights L and three series of storage battery cells 13,

connected across the circuit 12. A mul tiple blade switch S is shown arranged to accomplish the following general. results. When this switch is thrown to the right the three sections of storage battery are connected in parallel, and the armature A is connected as an exciter for exciting the field F of the other machine, while the field F 2 opposite point-s of the other two opposite points of this bridge being at the same time connected across the brushes of the armature A. This bridge is designed, as will be explained later to maintain a substantially constant potential across the brushes of the machine A regardless of variations of speed. An automatic switch X is also tween the negative terminal of the armature A and the corresponding conductor of the circuit 1-2; this switch being designed to close when the generator voltage has reached a value suitable for connection. to the circuit. When the switch S is thrown to the left, the batteries B 13 and B are connected in series, and the armatures A and A are connected in parallel across the battery, each armature having its field interposed in series therewith, so.that each machine operates as a series motor for starting the engine. When the switch S is thrown to the right, the various connections 'between the difierent circuits may be traced as follows: from the negative terminal of battery B by way of conductor 4, switchblade 6 and conductor 6 to the negative terminal of battery B also from the negative terminal of battery B via conductor 4, switch blade d and conductor 26 to the negative terminal of battery B thus connecting the three negative terminals of the batteries in parallel; also from the positive terminal of battery B via conductor 3, switch blade a and conductor '5 to the positive terminal of battery B also from the positive terminal of battery B via conductor 3, switch blade 0 and conductor 7 tothe positive terminal of battery B thus connecting the three positive terminals of the batteries in parallel. From the negative terminal of armature A via conductor the latter being mounted on the shaft of is permanentlyof the exciter is connected across a Wheatston-e' bridge Y,

'80 shown interposed bebrushes of armature A tive terminal of armature A via conductor 3 to the positive terminal of battery-B also from the positive terminal of exciter.

armature A via conductor 16, switch blade conductor 12, field winding F conductor 15, switch blade 9 and conductor 17 to the negative brush of excitcr armature A also from the terminals of the exciter field F via switch blades 2' and j and conductors 10 and 11 respectively to the opposite and 28 of the \Vheatstone bridge Y. The

"other two points of the \Vheatstone bridge 29 and 30 are connected by means of conductors 8 and 9 respectively, and switch blade@ in the last named circuit across the The lVheatstone bridge Y comprises two resistances R and R in opposite branches; these resistances having zero temperature coeflicient, or preferably an appreciable ative coeflicient, so that their resistance will decrease with increase of temperature. In the other two branches of the bridge are shown two resistances I and I having a high positive temperature coefficient, such as the well known iron wire resistances which serve to maintain a substantially constant current with wide variations of impressed voltage above a certain value. The function of this Wheatstone bridge is as follows: lVhen the impressed voltage across the points 29 and 30 reaches a critical value such that the drop in the resistances R and R due to the constant current maintained by the iron wire resistances I and I is just half of the potential across the brushes of the dynamo A the potential of the points 27 and 2S ofthe VVheatstone bridge will be equal, and no current will flow through the field F of the exciter. The voltage across the brushes of the armature A can, therefore, never reach this value since there would then be no excitation for the field of the cxeiter, and, therefore, no excitation for the field F As the speed of the machine increases, the voltage across the brushes of the armature A will approach this critical value, but by proper design of the machine, the difference between the actual voltage, and the limiting value, may be made very small over a wide range of speed. This voltage may be adjusted to maintain the batteries in a full state of charge Without appreciable overcharge, the dynamo A supplying the current for the lights, so long as its speed is sufiicient to develop the necessary electro-motive force. The automatic switch X, which is interposed between the negative brush of the dynamo A and the negative terminal of points 27 19, switch blade 0', conductors 20 and the battery B is provided with a shunt winding 24 connected by means of conductor 35 on one side and conductor 22, switch blade 6 and conductor 13 on the other side, across the brushes of dynamo A which serves to close the switch X when the po tential of the dynamo has risen to a suitable value. The series coil 23 serves to hold the switch closed so long as the current is supplied in the right direction from the dynam0. If, however, the speed of the dynamo is reduced sufficiently to produce a reversal of current from the battery into the dyname, this reversal in the series coil 23 will oppose the excitation of shunt coil 24, and

release the armature D, thus opening the circuit. When. the switch S is thrown to the left, the connections may be traced, as follows: From the negative terminal of battery B via conductor 4:, switch blade a and conductor 5 to the positive terminal of battery B. battery B via conductor 6, switch blades Z) and c, and conductor 7 to the positive terminal of battery B From the negative terminal of battery B via conductor 26, switch blade g, conductor 15, field winding F conductor-'12, switch blade f and conductor 13 to the negative brush of armature A also from the negative terminal of battery B via conductor 26, switch blade j, conductor 18,-field. winding F conductor 17 to the negative brush of armature A Positive terminal of battery B 'is connected by conductor 3 to the positive brush of. armature A also via conductors 3 and 14:, switch blade h and conductor 16to the positive brush of armature A Thus the two armatures A? and A are connected in parallel to act as series motors to start up the e11 gine.

It remains to describe the special clutch From the, negative terminal of devices by which the two trains of gearing are made selective in their operation. The gear wheels G and G are rigidly attached to the engine shaft. The pinions P and P are, however, free to revolve on the dynamo shaft, but are arranged to be mechanically connected thereto by means of the clutch devices shown in Figs. 2 and 3. Fi 2 is an enlarged end view of pinion P A hub M is shown keyed to the shaft,

while'an elastic'band clutch K is wrapped leased so that the dynamo vwill not drive the point N. This clutch K? is, however, wrappedabout the hub M in the reverse di- Q rection from the clutch K in Fig. 2.' It follows, therefore, that when the speed of the dynamo shaft becomes greater than that of the pinion P, the shaft will drive the pinion, thereby driving the engine. The pinion cannot, however, drive the dynamo shaft.

It will be seen, therefore, that by means of these two clutches. and gear trains, the dynamos A and A operating as motors will start up the engine by meansof the pinion P rotating in a counter-clock-wise' direction. The pinion P being smaller than P, the speed of the dynamo shaft will be greater than that of the pinion P, and the clutch K will not grip. The speed reduction of pinion I and ear G permits developing the high startlng torque necessary to overcome the compression in the cylinders O and C As soon, however, as the engine is started its speed will increase, and it will tend to drive the dynamos A and A As soon, however, as there is any tendency to" transmit power from the engine to the dynamo, the clutch K will be released, while the clutch K will grip, and the gear Gr and pinion P will then determine the speed of drive. The switch S which had been thrown to the left to makeconnection for operating the armatures A and,A'* as inotors may then be thrown to the-{'right, connecting the machines for operatidn' as gener-- ator and exciter, and as soon asi-the voltage of the machine A. has reached a suitable value the automatic switch X will close and the dynamo A will supply current to the circuit 1-2, and the batteries.

' Fig. 4 illustrates a different type of clutch in connection with pinion 1?; designed, however to accomplish the same results. In Fig. 4 the same hub M is shown keyed to the dynamo shaft. The pinion is provided with irregular shaped recesses 33 and 34 which provide taperin spaces between their surfaces and the cy indrical surface of the hub M In these spaces two steel balls 31 and 32 are free to revolve. When the dynamo shaft is rotatin in a counter-clock-wise direction faster t an the pinion P, the steel balls will roll into the narrow portion of the space between the hub and the pinion, and will jam in this s ace causing the dy namo shaft to drive the pinion, If, however, the pinion is driven at a speed greater than the dynamo shaft the steel balls will be released, and will revolve freely in the larger portion of the s ace, thus releasing the pinion from the sha t.

It will be understood that any type of clutch which will transmit the driving force in one direction only may be used, and I do not confine myself to any particular type of clutch. Any of the well known means for transmitting mechanical power between the two shafts may also be employed.

Having described my invention what I claim and desire to secure by Letters Patent 4 '1. In combination, an internal combustion engine, a storage battery and its consumption circuit, dynamo-electric apparatus including, two mechanically connected armatures, transmission gear interposed between the engine and the dynamo-electric apparatus, and electrical connections including switches for running both armatures asmotors from the battery to start the engine, and for running one armature as an exciter for the other operating as a generator to charge the battery and supply the consumption cir-- cuit. i

2. In combination, an internal combustion engine, a storage battery and its consumption circuit, dynamo-electric apparatus including two mechanically, connected armatures, selective transmission gear interposed between the engine and the dynamo-electric apparatus, and adapted to start the engine from the dynamo at one speed ratio and to. run the dynamo from the engine at lower ratio of dynamo to engine speed, and electrical connections including switches for running both armatures as motors from the battery to start the en ine and for running one armature as an exciter for the otheropcrating as a generator to charge the battery and supply t e consumption circuit.

3. In combination an internal combustion engine, a storage battery, two armatures mechanically connected together'and to the-engine, circuit connections for running bothv armatures from the storage battery as motors to startthe engine, a field regulator and circuit connections for permitting one of said armatures to act' as a dynamo when driven by the engine to charge the battery and for causing the field regulator and the I other armature operating as an exciter to regulate the charging voltage as the engine speeds up.

In testimony whereof I have hereunto signed my name.

JOSEPH LESTER WOODBRIDGE.

Witnesses:

J. H. TRACY, R. A. WHITSDONE, Jr. 

